Brisbane Roar capped off its season of dominance in the most dramatic of fashions, fighting back from two goals down in extra time to clinch the A-League title in a penalty shoot-out over Central Coast Mariners.

The Roar's unbelievable campaign and 27-game unbeaten streak were just three minutes away from being unceremoniously snapped in front of 50,168 fans after Adam Kwasnik and Oliver Bozanic scored in the first half of extra time.

But Brisbane replied with one of the most stirring comebacks in A-League history to level the game at 2-2.

Substitute Henrique pulled a goal back in the 117th minute after good lead-up play by strike partners Jean Carlos Solorzano and Thomas Broich before Erik Paartalu's header with the last touch of the match remarkably sent the game to penalties.

Brisbane goalkeeper Michael Theoklitos, a two-time winner with Victory, then stepped up to the occasion with two tremendous saves in the shoot-out to deny both Daniel McBreen and Pedj Bojic.

Cult hero Henrique slotted home the winning penalty to seal a 4-2 score and send the Roar players and the parochial Lang Park crowd into raptures.

"It's been an extraordinary season and I should have expected an extraordinary finish," coach Ange Postecoglou told Granstand, his side having accomplished a similar feat in the second leg of the major semi-final against the Mariners a fortnight ago.

"We persisted and we never give up, and I think that's indicative of our whole season.

"It was a memorable final, I'm sure people will be talking about it for a long time, but as I said we needed to prove ourselves.

"We got tested again but that's the sign of a champion team I think."

Young Mariners keeper Mathew Ryan won the Joe Marston medal for player of the match for his fantastic effort in keeping the Roar at bay for almost two hours.

Brisbane becomes the fourth different winner of the A-League title behind Melbourne Victory, Sydney FC (two each) and Newcastle United.

Central Coast is still yet to win an A-League grand final from three attempts in the last six years.

Kwasnik, who was part of both those defeats to Sydney and Newcastle in seasons one and three respectively along with skipper Alex Wilkinson, thought he had broken the club's unwanted record.

He popped up to bundle home the opener from a corner six minutes into extra-time and then, after his initial shot was blocked by a charging Theoklitos, provided an assist for Bozanic to touch home the easiest of finishes just seven minutes later.

"We've experienced it before and ... there's not a lot to say. It's just despair and that's football - it can be a beautiful game but it can be a cruel game as well," Kwasnik said.

"I don't know what the game of football was like to watch but hopefully it was exciting. In the end 2-0 up is a dangerous scoreline but we should have had it wrapped up.

"Credit to Brisbane Roar, they're a super team and that's why they're 28 games unbeaten."

The victory holds special significance for the club and its supporters after many parts of Brisbane were inundated by floodwaters early this year, affecting many homes and businesses and even forcing the Roar to abandon their iconic stadium.

Flowing first half

Both sides had both the fans and purists smiling in an entertaining and free-flowing first half which produced some fantastic end-to-end football.

Kwasnik, preferred ahead of McBreen to partner Matt Simon up front, had two headed efforts denied, including one cleared off the line by Brisbane captain Matt McKay in the 11th minute.

The outstanding Kwasnik also had an audacious lob from 40 yards just loft over the crossbar as Theoklitos was caught napping off his line.

But it was Simon who arguably had the chance of the first 45 minutes, fluffing his close range shot after Kwasnik delivered a perfect ball from the right flank on 36 minutes.

The Roar, looking to German import Thomas Broich to make inroads down the left, took control of the encounter as the break approached and had a handful of their own opportunities.

Young midfielder Mitch Nichols was denied three times, including rattling the crossbar with a right-foot volley from a corner moments after Simon's gilt-edged miss.

Brisbane's hold on the game became more obvious in a more-tense second half as teeming rain from a typical south-east Queensland storm engulfed the stadium.

But the Roar of unsuccessful seasons' past reared its ugly head as they failed to make the most of superior possession and the brilliant Ryan showed why he was recognised as young player of the year with a quality display between the posts.

That set the scene for an astonishing extra-time raid which saw Theoklitos produce two amazing reaction saves in a matter of minutes, before Central Coast broke through.

The script had a final twist however, as the Mariners' efforts were matched by an even more miraculous finish by the eventual champions as they stole back the title.